<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>on_off_toggle</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <div class="container">
        <input type="checkbox" id="toggle">
        <label for="toggle"></label>
    </div>

    <script>
        const toggle = document.querySelector('#toggle')

        toggle.addEventListener('click', () => {
            document.body.classList.toggle('on');
        }, false)
    </script>
</body>
</html>